A transportable device for heating foodstuffs includes a container for receiving the foodstuff as well as a closed-off heating chamber which adjoins the container and is thermally coupled thereto while simultaneously being hermetically separated therefrom via a shared, thermally-conductive wall. The heating chamber includes a first chamber and a second chamber that are separated by a water vapor-permeable wall. In the first chamber is a substance or a substance mixture which, when a liquid, preferably water, is supplied, generates heat in an exothermic chemical reaction with water vapor being formed. In the second chamber, a zeolite is located which can adsorb the water entering from the first chamber via said water vapor-permeable wall, generating heat. A transportable heating element which can be used in the device contains a hermetically-sealed heating chamber that adjoins a thermally-dissipating outer wall.